Prenatal Exposure to Fine Particulate Matter Components Linked to Autism Spectrum Disorder Risk

FRIDAY, Oct. 31, 2025 (HealthDay News) — Prenatal exposure to specific components of fine particulate matter (PM_2.5) and postnatal ozone exposure are associated with an increased risk for autism spectrum disorder (ASD), according to a study published online Oct. 23 in JAMA Network Open.

Maxime Cloutier, from Health Canada in Ontario, and colleagues conducted a cohort study to examine associations between prenatal and first year-of-life exposure to PM_2.5 components and ASD diagnosis by age 5 years. The cohort study included singleton live births from Ontario hospitals between April 1, 2002, and Dec. 31, 2022, with gestational age 36 to 42 weeks and birth weight of 500 to 6,800 g.

Among 2,183,324 births, the researchers found that prenatal exposure to PM_2.5, sulfate, and ammonium and postnatal exposure to ozone were associated with ASD. Per one-interquartile range increase, the hazard ratios were 1.15 and 1.12 for sulfate and ammonium, respectively. There was no association for PM_2.5 mass excluding sulfate and ammonium during their respective critical windows with ASD. Ozone exposure during weeks 26 to 30 and during the first year was associated with ASD (hazard ratios, 1.03 and 1.09, respectively).

“These findings underscore the potential importance of early-life environmental exposures and reinforce the need for public health strategies to reduce air pollution, particularly in urban and socioeconomically disadvantaged communities,” the authors write.

Abstract/Full Text